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<div class="titlepage"><div><div><h3 class="title">
<a name="building.choosing_a_boost_python_library_"></a><a class="link" href="choosing_a_boost_python_library_.html" title="Choosing a Boost.Python Library Binary">Choosing a
      Boost.Python Library Binary</a>
</h3></div></div></div>
<div class="toc"><dl class="toc">
<dt><span class="section"><a href="choosing_a_boost_python_library_.html#building.choosing_a_boost_python_library_.the_dynamic_binary">The
        Dynamic Binary</a></span></dt>
<dt><span class="section"><a href="choosing_a_boost_python_library_.html#building.choosing_a_boost_python_library_.the_static_binary">The
        Static Binary</a></span></dt>
</dl></div>
<p>
        If—instead of letting Boost.Build construct and link with the right libraries
        automatically—you choose to use a pre-built Boost.Python library, you'll
        need to think about which one to link with. The Boost.Python binary comes
        in both static and dynamic flavors. Take care to choose the right flavor
        for your application. <a href="#ftn.building.choosing_a_boost_python_library_.f0" class="footnote" name="building.choosing_a_boost_python_library_.f0"><sup class="footnote">[3]</sup></a>
      </p>
<div class="section">
<div class="titlepage"><div><div><h4 class="title">
<a name="building.choosing_a_boost_python_library_.the_dynamic_binary"></a><a class="link" href="choosing_a_boost_python_library_.html#building.choosing_a_boost_python_library_.the_dynamic_binary" title="The Dynamic Binary">The
        Dynamic Binary</a>
</h4></div></div></div>
<p>
          The dynamic library is the safest and most-versatile choice:
        </p>
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
              A single copy of the library code is used by all extension modules
              built with a given toolset. <a href="#ftn.building.choosing_a_boost_python_library_.the_dynamic_binary.f0" class="footnote" name="building.choosing_a_boost_python_library_.the_dynamic_binary.f0"><sup class="footnote">[4]</sup></a>
            </li>
<li class="listitem">
              The library contains a type conversion registry. Because one registry
              is shared among all extension modules, instances of a class exposed
              to Python in one dynamically-loaded extension module can be passed
              to functions exposed in another such module.
            </li>
</ul></div>
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<div class="section">
<div class="titlepage"><div><div><h4 class="title">
<a name="building.choosing_a_boost_python_library_.the_static_binary"></a><a class="link" href="choosing_a_boost_python_library_.html#building.choosing_a_boost_python_library_.the_static_binary" title="The Static Binary">The
        Static Binary</a>
</h4></div></div></div>
<p>
          It might be appropriate to use the static Boost.Python library in any of
          the following cases:
        </p>
<div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: disc; ">
<li class="listitem">
              You are <a href="https://docs.python.org/2/extending/extending.html" target="_top">extending</a>
              python and the types exposed in your dynamically-loaded extension module
              don't need to be used by any other Boost.Python extension modules,
              and you don't care if the core library code is duplicated among them.
            </li>
<li class="listitem">
              You are <a href="https://docs.python.org/2/extending/embedding.html" target="_top">embedding</a>
              python in your application and either:
              <div class="itemizedlist"><ul class="itemizedlist" style="list-style-type: circle; ">
<li class="listitem">
                    You are targeting a Unix variant OS other than MacOS or AIX,
                    where the dynamically-loaded extension modules can “see”
                    the Boost.Python library symbols that are part of the executable.
                  </li>
<li class="listitem">
                    Or, you have statically linked some Boost.Python extension modules
                    into your application and you don't care if any dynamically-loaded
                    Boost.Python extension modules are able to use the types exposed
                    by your statically-linked extension modules (and vice-versa).
                  </li>
</ul></div>
            </li>
</ul></div>
</div>
<div class="footnotes">
<br><hr style="width:100; text-align:left;margin-left: 0">
<div id="ftn.building.choosing_a_boost_python_library_.f0" class="footnote"><p><a href="#building.choosing_a_boost_python_library_.f0" class="para"><sup class="para">[3] </sup></a>
          Information about how to identify the static and dynamic builds of Boost.Python
          on <a href="http://boost.org/more/getting_started/windows.html#library-naming" target="_top">Windows</a>
          / <a href="http://boost.org/more/getting_started/unix-variants.html#library-naming" target="_top">Unix
          variants</a>
        </p></div>
<div id="ftn.building.choosing_a_boost_python_library_.the_dynamic_binary.f0" class="footnote"><p><a href="#building.choosing_a_boost_python_library_.the_dynamic_binary.f0" class="para"><sup class="para">[4] </sup></a>
                Because of the way most *nix platforms share symbols among dynamically-loaded
                objects, I'm not certain that extension modules built with different
                compiler toolsets will always use different copies of the Boost.Python
                library when loaded into the same Python instance. Not using different
                libraries could be a good thing if the compilers have compatible
                ABIs, because extension modules built with the two libraries would
                be interoperable. Otherwise, it could spell disaster, since an extension
                module and the Boost.Python library would have different ideas of
                such things as class layout. I would appreciate someone doing the
                experiment to find out what happens.
              </p></div>
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<td align="right"><div class="copyright-footer">Copyright © 2002-2015 David
      Abrahams, Stefan Seefeld<br>Copyright © 2002-2015 David Abrahams, Stefan Seefeld<p>
        Distributed under the Boost Software License, Version 1.0. (See accompanying
        file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
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